There are about 950 million sheep in the world, out of which more than 177.8 million sheep are in Australia alone. In winter, we all wear woollen clothes to protect our body from cold and also keep our body warm. The wool we wear comes from the fleece of sheep. Good quality of woof comes from Merino sheep — a specially bred sheep which originally came from Spain. However, most wool is now produced in Australia. The largest sheep station in the world is the Commonwealth Hill in the north-west of South Australia. It grazes between 5000 to 7000 sheep. Do you know how do the woollen clothes keep our body warm?
We know that the internal temperature of our body is 98.4°F but the skin temperature is about 91°F. We feel warm or cold only if a part of our body comes into contact with a body of different temperature.
When the temperature of our surroundings is about 65°F we feel quite comfortable because the temperature of our body is about 25° more than this temperature. In such a state our body continuously radiates heat. If the temperature falls below it, we feel cold. Under this condition we wear clothes which are bad conductors of heat. Wool is a bad conductor of heat and its fibres can trap air in between themselves.
Now air is also a bad conductor of heat but wool is even more and so our body does not radiate much heat. That is why we feel warmth when we wear woollen clothes, which are also heavy.
An important property of wool is that it can absorb moisture. About 1 kg of wool can absorb almost 120 gm of water vapour and despite this wool would appear dry. Due to this property wool can also absorb the sweat from the body which provides warmth to the body. The absorption of moisture makes the wool slightly warm.
Today sheep are used mostly for wool and meat. Modern sheep have been specially bred to give the best combination of wool and meat.
